Hydrocarbon reactions



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\ carhon-to-carb0n bonds.

ted "with 2,2llt,2'li

itilfihhflill l REACTHUNS Aristid if. Grease, iithicago, 111., assignor to Universal will lirotlncts Company, Chicago, 111., a corporation of Delaware lilo llllrawinn.

application @ctoher 21, 1939,

Serial No. W058i it @laims.

This application is a contlnuation-in-part of my co-pending application Serial No. 211,017 filed May 31, 1938.

This invention relates more particularly to a 1,. process involving the interaction oi paramn hydrocarbons of varying molecular weight and structure to form reaction products of an in termediate characterwhile using catalysts which have been found experimentally to accelerate the desired reactions.

The invention is more particularly concerned with a novel method for converting relatively high boiling paraflin hydrocarbons into lower boiling hydrocarbons of selected boiling range by reactions involving a method of thermal decomposition and a minimum of the production of waste byproducts such as gases and heavy liquids boiling outside the range oi motor fuel.

it is generally assumed that the paramn hydrocarbons are unreactive among themselves and that when reactions occur at elevated tempera--- tures, they follow primary decomposition reactions which produce active unsaturated radicals after the release oi hydrogen and the rupture oi When these reactions are brought about by strictly thermal methods they correspond exactly to ordinary reactions of cracking as observed when petroleum fractions are thermally treated for the production of gasoline and there is a corresponding production of fixed gases and high molecular weight materials, though the exact amounts of these byproducts will vary with the type of paraflin or parafin mixture treated and the conditions of operation.

at the present time attention is being ill rooted Lo the production of high antiknoclt motor heels of an iso-parafiinic character. These are produced by polymerizing low molecular Weight oieiins to form simple and mixed dimers and trimers thereof and then hydrogenatine the liquid nicno-olefins to produce paramns. The nature of the polymerization reactions is apparently such that the polymers are of an isomeric L or branched chain structure and their hydrouenated products have consequently a high antilrnoolr value. The compound known as iso-oc- Lane. or 2,2, t-trimethyl pentane which is used as a standard of reference in giving lrnocir rating of individual hydrocarbons or gaeolines may be (Cl. tilt-10) produced by catalytically polymerizing iso-butene to form 2,2,4-trimethy1 pentane and hydrogenatlng the latter. In the steps oi polymerization and hydrogenation in these cases there are frequently undesirably large amounts of paraifinic hydrocarbons boiling above the range desired in the finished products and the present invention is in one aspect concerned with the reconversion of these high boiling paraiflns into paraflin hydrocarbons boiling within the desired range.

In one specific embodiment, the present invention comprises the interaction of relatively high molecular weight paraifin hydrocarbons with lower molecular weight iso-paraflin hydrocarbons in the presence of boron fluoride-hydro gen fluoride catalysts.

A typical reaction which falls within the scope of the present invention is that which occurs between normal dodecane and iso-butane. Although the mechanism is not exactly known, the following equations are suggested:

dodecane octane 'butene (2) UiHli CiHlO CsHm butene lac-butane octane it will be seen from the above equations the presumption is that under the influence of the preferred catalyst, the high molecular weight paraihn undergoes a splitting reaction to form a molecule of parafifin and a molecule of olefin and the molecule of olefin then reacts with iso-butane to form an octane by a type of alkylation reaction. it is further to be observed that there is complete conversion of the high boiling paraffln into the lower boiling paraffin although this theoretical yield is not always possible of attainment in practice.

Similarly other reactions may be brought about between high boiling paraflins and lower boiling iso-paraflins. For example, reactions may be brought about between catane and iso-butane, cetane and iso-hexane, cetane and iso-octane although one of the principal applications of the present process is in the reconversion of paraflins boiling above octanes, which are produced in processes aimed at the production of iso-octane, back to the desired product. The iso-paramns may be obtained from any source although the 50 most readily utilizable source of iso-butane is the butane fraction produced from cracked gas mixtures after olefins have been removed by polymerization or alkylation reactions and residual parafiins fractionated. Iso-butane and other low boiling iso-paraffins essential for the reaction may be obtained by isomerization of the corresponding normal paraffins by recognized methods.

Reactions of the present character may be brought about either by batch or continuous methods. In batch operation the high-boiling parafflns and the lower-boiling iso-paraffins may be charged to a pressure vessel along with regulated amounts of boron fluoride and hydrogen fluoride while maintaining a suitable temperature for a'time corresponding to best yields of the desired product. The interior of the vessel should preferably be of a material such as nickel which is resistant to the corrosive action of boron and hydrogen fluorides. When working with different combinations of hydrocarbons to form products of intermediatemolecular weight, temperatures varying over a considerable range may be employed if these are properly inter-related with the time of exposure to reaction conditions. This range of temperatures is rather wide and is comprised within the approximate limits of -30 to +150 C. Good results have been obtained at temperatures of the order of C. with long times of reaction in contact with the catalyst, characteristic results being shown in following examples.

Continuous operations may be brought about by passing proportioned mixtures of hydrocarbons and catalysts through tubular elements of sufflcient length to provide the requisite time factor and of design calculated to induce turbulence.

After the reactions have been completed the catalytic compound may be separated and recovered by fractionation and the hydrocarbon products further fractionated to obtain the desired intermediate hydrocarbon product and recover heavier and lighter materials which may be recycled and further reacted.

The following example is introduced to indicate the type of results normally obtainable in the application of the process although not with the purpose of unduly limiting the invention's proper scope.

A dodecane fraction was reacted with isobutane in a stainless steel autoclave equipped with a mechanical stirrer. The following tabulation shows the principal data obtained in connection with the run:

Average pressure, lb. per sq. in 38 Contact time, hours 43 Temperature, C 0 C12H2a charged, parts by weight 69.5 i-CiHio charged, parts by weight 48.0

Boron fluoride charged, parts by weight 14.8 Hydrogen fluoride charged, parts by weight 3.7

Recovered:

Upper layer 112 Lower layer 11 This was a cut from hydrogenated B-B polymer boiling at 185l92 O. n=1.4302 and it was completely saturated.

It will be seen from the above data that about one-half of the original iso-butane charged was consumed in the reaction and that the reaction produced liquid hydrocarbons from C5 to C in an amount equal to about 47% of the total dodecanes and iso-butane reacted. These fractions all boiled within the range of motor fuel and had a sufllciently high antiknock value to be directly blended with airplane fuel.

The following table gives a general summary of the reaction on a molal basis.

Moles Moles Moles charged reacted formed Isobutaue, 04H" 83 .40 Dodecane, CnHgs 41 30 Ismoctane. 05H]: 13

I claim as my invention:

1. A process for interacting relatively high molecular weight parafiin hydrocarbons with lower molecular weight iso-parafiin hydrocarbons to form paraflin hydrocarbons of intermediate molecular weight which comprises contacting said hydrocarbons with catalytic material comprising essentially boron fluoride and hydrogen fluoride, at temperatures within the approximate range of 30 to +150 C. and for times adequate to produce optimum yields of desired products.

2. A process for interacting relatively high molecular weight normal paraflin hydrocarbons with lower molecular weight iso-paraflin hydrocarbons to form paraflin hydrocarbons of intermediate molecular weight which comprises contacting said hydrocarbons with catalytic material comprising essentially boron fluoride and hydrogen fluoride, at temperatures within the approximate range of -30 to +150 C. and for times adequate to produce optimum yields of desired products.

3. A process for interacting paraflin hydro- I carbons of higher molecular weight than octane 

